Of the 20 million American diabetics, 10% develop foot ulcers with a 16-fold increase risk of amputation. New clinical therapies with growth factors and skin substitutes have increased healing rates to 50%. A novel microcarrier cell-therapy platform (RMCT platform) will be investigated in this application for the use on diabetic foot ulcers. The microcarrier cell-therapy platform is a simple manufacturing and application device when compared to the skin substitutes currently available. The focus of the research proposed in this Phase I proposal is to address the issue of keratinocyte viability and biological status in the wound environment. Examining the number of cells present, their viability and their biological activities at various times after application to the wound will provide key information on the status of the cells. The Phase I studies will be outlined in two specific aims. In Aim 1 studies, we will be harvesting RMCT platforms that have been in contact with wound tissue for up to seven days and evaluating the platforms for the presence of viable keratinocytes. It is important, we believe to know how cell viability changes over time in the wound tissue in order to optimize the use of this novel therapeutic approach. It is also important for regulatory purposes to know what happens to the xenografted cells under the conditions of use in wound treatment. The studies described in aim 2 constitute our experimental design for characterizing the function of human keratinocyte function when exposed to the wound environment in RMCT platforms. Studies have shown that such treatment promotes the wound-healing process. These studies outline initial efforts for looking at how this may come about.